doc: Reword text to be less verbose in r.geomorphon (#5034)

* doc: reword text to be less verbose r.geomorphon.html

* update remain to remains in r.geomorphon.html

Co-authored-by: Veronica Andreo <veroandreo@gmail.com>

---------

Co-authored-by: Veronica Andreo <veroandreo@gmail.com>

raster/r.geomorphon/r.geomorphon.html

@@ -33,9 +33,9 @@ <h3>What is geomorphon:</h3>
 different from the horizon. Two lines-of-sight are necessary due to zenith
 LOS only, does not detect positive forms correctly.
 
-<p> There are 3**8 = 6561 possible ternary patterns (8-tuples). However by
-eliminating all patterns that are results of either rotation or reflection
-of other patterns we get a set of 498 patterns remain referred as geomorphons.
+<p> There are 3**8 = 6561 possible ternary patterns (8-tuples). By removing
+all patterns that are the result of either rotation or reflection of other 
+patterns, a set of 498 patterns remains, referred to as geomorphons.
 This is a comprehensive and exhaustive set of idealized landforms that are
 independent of the size, relief, and orientation of the actual landform.